Method of manufacturing composite products comprising a carbohydrate-based binder

ABSTRACT

The present invention relates to the use of an amine compound comprising at least one, preferably at least two amine functions, wherein the amine functions are primary or secondary amines, to reduce the level of furfural and/or hydroxymethylfurfural in a carbohydrate-based binder or binder composition and/or escaping in the course of preparation, cross-linking and/or curing of carbohydrate-based binders. Preferably, the carbohydrate-based binder is obtained from a carbohydrate-based binder composition comprising a carbohydrate component and a cross-linker and possibly reaction product of carbohydrate component and cross-linker, wherein the cross-linker is selected from ammonium salts of inorganic acid, carboxylic acids, salts, ester or anhydride derivatives thereof, and/or combinations thereof.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.18/084,012, filed Dec. 19, 2022, which is a continuation of U.S.application Ser. No. 16/828,896, filed Mar. 24, 2020, which is acontinuation of U.S. application Ser. No. 16/306,557 (now U.S. Pat. No.10,597,516), filed Dec. 1, 2018, which is a U.S. national counterpartapplication of International Application Serial No. PCT/EP2017/062430,filed May 23, 2017, under 35 U.S.C. § 371, which claims priority to GBApplication Serial No. 1609616.6, filed Jun. 2, 2016, the disclosures ofwhich are hereby incorporated herein by reference.

TECHNICAL FIELD

The present invention relates to a method of manufacturing compositeproducts, more specifically composite products comprising fibers,particles, chips, strips, and/or sheets bonded with a binder. Examplesof such composite products include woven and non-woven fiber mats, suchas mineral fiber mats, for example mineral wool mats (glass wool, rockwool), mineral fiber veils, prepregs, engineered wood products, such aswood boards, for example MDF (Medium Density Fiber Boards), particleboards, oriented strand boards (OSB), plywood etc.

BACKGROUND

The trend to more sustainable and environmentally friendly products hasdirected the development of such composite products away from the use offormaldehyde-based binders towards the use of formaldehyde-free binders.Among such formaldehyde-free binders, carbohydrate-based bindersrepresent an important share.

In the context of this description, “formaldehyde-free” is understood tomean “comprising less than about 1 ppm formaldehyde based on the weightof the composition and not liberating substantial formaldehyde”.

Carbohydrate based binders include binders obtained by the reaction of acarbohydrate with a nitrogenous compound, such as Maillard-type binders,by the reaction of a carbohydrate with an organic acid, and otherbinders obtained from starting materials that include a carbohydrate.

Carbohydrates are readily available in nature. Sources are animalderived products such as chitosan (derived from crustacean shells) andplant derived products, including but not limited to starch, syrup,molasses and cellulose. These carbohydrates also called polysaccharidesare macromolecules made up by saccharide units. An advantageous sourceof carbohydrate raw materials can be found in recycled materials, suchas recycled municipal solid waste, recycled paper and/or sugar canebagasse, and/or wood. Depending on the source and/or on the hydrolysisprocess used to degrade the polysaccharides, different polysaccharidesor polysaccharide compositions may be obtained. In certain applications,smaller molecules may be preferred, such as short chain polysaccharides,oligosaccharides or even saccharide units. Again, depending on thesource and/or hydrolysis process conditions, different saccharides orsaccharide mixtures may be obtained. While cellulose hydrolysis willgenerate essentially C6 sugars, preferably C-6 reducing sugars, e.g.dextrose, hemicellulose will generate a large fraction of C5 sugars,like xylose for instance.

In raw materials resulting from hydrolysis of higher molecular weightcarbohydrates, the level of C5-sugars or five membered ring sugars hasbeen found to vary from 5 to 70 wt. %, preferably from 10, from 15, from20 or even from 25% by weight, and up to preferably 60 wt. %, 50 wt. %,45 wt. % or 40 wt. %.

It is known that saccharides may give rise to furfural and/orhydroxymethylfurfural formation in the course of the binder preparationand/or binder curing process. While starting from raw materials asdiscussed above to produce a binder may be of interest for severalreasons, such as the availability of raw materials and costs of themanufacturing process, it has been found that the presence of C-5 sugarsin the carbohydrate component gives rise to increased furfural and/orhydroxymethylfurfural generation in the course of the binder preparationand/or curing process. Furfural and/or hydroxymethylfurfural may beundesirable beyond a certain level, for environmental and/or healthreasons, but also because of regulatory requirements. There is thus aneed to reduce the level of furfural and/or hydroxymethylfurfuralgenerated in the course of binder preparation and/or curing.

SUMMARY

It has now been found that the level of furfural and/orhydroxymethylfurfural in the binder composition and/or escaping duringbinder preparation and/or curing may be reduced by addition of an aminecompound, preferably an amine compound comprising at least one,preferably at least two amine functions, wherein the amine functions areprimary or secondary amines.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a chart showing the variation of furfural content in a binderderived from a carbohydrate component comprising dextrose and xylose invarying amounts, cross-linked with ammonium sulphate, as well as theeffect of added hexamethylenediamine.

DETAILED DESCRIPTION

The present invention hence provides a method for the preparation of acomposite product comprising fibers and/or particles and/or sheetmaterial bonded with a carbohydrate-based binder comprising (i)providing a binder composition comprising a carbohydrate component and across-linker and possibly reaction product of carbohydrate component andcross-linker, wherein the cross-linker is selected from ammonium saltsof inorganic acid, carboxylic acids, salts, for example ammonium saltsthereof, ester or anhydride derivatives thereof, and/or combinationsthereof, (ii) adding to the binder composition an additional amount offrom 0.5 to 10 wt. %, preferably 1 to 6 wt. % (based on the total dryweight of the binder composition) of an amine compound comprising atleast one, preferably at least two amine functions, wherein the aminefunctions are primary or secondary amines, (iii) applying thecomposition obtained under (ii) onto the fibers, particles and/or sheetmaterial, and (iv) subjecting the product obtained under (iii) to heatand possibly pressure to effect drying and/or curing.

As used herein, “ammonium” means NH₄ ⁺.

The term “binder composition” as used herein means all ingredientsapplied to the matter to be bound and/or present on the matter to bebound, notably prior to curing, (other than the matter and any moisturecontained within the matter) including reactants, solvents (includingwater), any carbohydrate component, any crosslinker and any additives.

The term “binder” is used herein to designate a thermoset binder resinobtained from the “binder composition”.

The term “cured” means that the components of the binder compositionhave been subjected to conditions that lead to chemical change, such ascovalent bonding, hydrogen bonding and chemical crosslinking, which mayincrease the cured product's durability and solvent resistance, andresult in thermoset material.

The term “dry weight of the binder composition” as used herein means theweight of all components of the binder composition other than any waterthat is present (whether in the form of liquid water or in the form ofwater of crystallization).

The term “crosslinker” as used herein comprises compounds that arecapable of reacting with the carbohydrate component to formramifications or reticulations of the said carbohydrate component. As isunderstood, the cross-linker is different from and does not comprise anyamine compound as defined above.

Carbohydrates as used herein comprise monosaccharides, disaccharides,oligosaccharides and polysaccharides and/or combinations thereof. Theymay be reducing sugars, such as dextrose, or non-reducing sugars, suchas sucrose, that may produce reducing sugars in situ. They mayadvantageously be a low MW polysaccharide. In one embodiment, thecarbohydrate component may be selected from or derived from molasses,starch, starch hydrolysates, dextrines and derivatives, cellulosehydrolysates, hemicellulose hydrolysates or mixtures thereof. Asmentioned before, the carbohydrate component may be obtained from animalderived material and/or plant derived material. In a preferredembodiment, the carbohydrate component is derived from higher molecularweight carbohydrates, wherein the level of C5-sugars or five memberedring sugars varies from 10 to 70 wt. %, preferably from 15, from 20 oreven from 25% by weight, and up to preferably 60 wt. %, 50 wt. %, 45 wt.% or 40 wt. %.

Suitable amine compounds comprise at least one, preferably at least twoamine functions, wherein the amine functions are primary or secondaryamines, the amine compound comprising preferably at least one primaryamine function. The amine compound is advantageously selected fromaliphatic monoamines, wherein the aliphatic group is a straight orbranched saturated or unsaturated alkyl or hetero-alkyl chain having 2to 24 C-atoms or cycloalkyl or cyclohetero-alkyl or an aromatic carbonring structure, each possibly substituted by hydroxy, carboxyl, halo,cyanate, sulfonyl or thiol, from compounds of general formula H₂N-Q-NH₂wherein Q is a straight or branched alkanediyl, heteroalkanediyl having2 to 24 C-atoms, cycloalkanediyl, or cylcoheteroalkanediyl, an aromaticcarbon ring structure, possibly substituted by hydroxy, carboxyl, halo,cyanate, sulfonyl and/or thiol, or from proteins, such as whey or soyprotein, possibly modified or denatured, or from poly(primary amines)having a molecular weight of 5000 or less and 10 wt. % or more ofprimary amine groups based on the weight of the polyamine. According toa preferred embodiment, Q is a C₆ alkanediyl. According to anotherembodiment, Q may be a cyclohexanediyl, cyclopentanediyl orcyclobutanediyl, or a divalent benzyl radical. In this context, itshould be noted that certain authors prefer using the term “alkyl”instead of the chemically more correct “alkanediyl” nomenclature; thesame chemical group is meant. As used herein, the term “alkanediyl”means a chain of carbon atoms, which may optionally be branched,preferably of limited length, including —C₁-C₂₄—, —C₁-C₁₂—, —C₁-C₈—,—C₁-C₆—, and —C₁-C₄—. Shorter alkanediyl groups may add lesslipophilicity to the compound and accordingly will have differentreactivity towards the reducing sugar reactant and/or solubility. Asused herein, the term “cycloalkanediyl” means a chain of carbon atoms,which may optionally be branched, where at least a portion of the chainis cyclic and also includes polycyclic structures, for example,cyclopropanediyl, cyclopentanediyl, cyclohexanediyl,2-methylcyclopropanediyl, 2-ethylcyclopentanediyl, adamantanediyl.Furthermore, the chain forming cycloalkanediyl is advantageously oflimited length, including —C₃-C₂₄—, —C₃-C₁₂—, —C₃-C₈—, —C₃-C₆—, and—C₅-C₆—. Shorter alkanediyl chains forming cycloalkanediyl may add lesslipophilicity to the compound and accordingly will have a differentbehaviour.

The poly(primary amine) may be selected from polyetheramines,polyethyleneimines, polyethyleneimine containing copolymers and blockcopolymers, polyvinyl amines, (co)polymers of n-aminoalkyl(meth)acrylates, such as aminoethyl methacrylate.

In illustrative embodiments, the polyamine is selected from a groupconsisting of a diamine, triamine, tetraamine, and pentamine. In oneembodiment, the polyamine is a diamine selected from a group consistingof 1,6-diaminohexane and 1,5-diamino-2-methylpentane. In one embodiment,the diamine is 1,6-diaminohexane. In one embodiment, the polyamine is atriamine selected from a group consisting of diethylenetriamine,1-piperazineethaneamine, and bis(hexamethylene)triamine. In anotherembodiment, the polyamine is a tetramine such as triethylenetetramine.In another embodiment, the polyamine is a pentamine, such astetraethylenepentamine.

The relevant amine compound may also be selected from aminoacids. Someare primary monoamines; others are di-primary amines. Lysine is anexample of a diamine which has shown to perform well and which isreadily available for applications under consideration.

Another amine compound family that has shown to perform well are ureabased compounds, more particularly urea. Urea comprises two —NH₂ groupswhich are available for reaction.

As used herein the term “carboxylic acid” includes monocarboxylic acidsas well as polycarboxylic acids, salts, ester and anhydride derivativesthereof. The term “polycarboxylic acid” indicates a dicarboxylic,tricarboxylic, tetracarboxylic, pentacarboxylic, and monomericpolycarboxylic acids, as well as polymeric polycarboxylic acids, andcombinations thereof. In one aspect, the polycarboxylic acid ammoniumsalt reactant is sufficiently non-volatile to maximize its ability toremain available for reaction with the carbohydrate reactant of aMaillard reaction (discussed below). In another aspect, thepolycarboxylic acid ammonium salt reactant may be substituted with otherchemical functional groups. Monomeric polycarboxylic acid comprisesdicarboxylic acid, including, but not limited to, unsaturated aliphaticdicarboxylic acids, saturated aliphatic dicarboxylic acids, aromaticdicarboxylic acids, unsaturated cyclic dicarboxylic acids, saturatedcyclic dicarboxylic acids, hydroxy-substituted derivatives thereof, andthe like. Polycarboxylic acid(s) may be a tricarboxylic acid, including,but not limited to, unsaturated aliphatic tricarboxylic acids, saturatedaliphatic tricarboxylic acids, aromatic tricarboxylic acids, unsaturatedcyclic tricarboxylic acids, saturated cyclic tricarboxylic acids,hydroxy-substituted derivatives thereof, and the like. It is appreciatedthat any such polycarboxylic acids may be optionally substituted, suchas with hydroxy, halo, alkyl, alkoxy, and the like. In one variation,the polycarboxylic acid is the saturated aliphatic tricarboxylic acid,citric acid. Other suitable polycarboxylic acids are contemplated toinclude, but are not limited to, aconitic acid, adipic acid, azelaicacid, butane tetracarboxylic acid dihydride, butane tricarboxylic acid,chlorendic acid, citraconic acid, dicyclopentadiene-maleic acid adducts,diethylenetriamine pentaacetic acid, adducts of dipentene and maleicacid, ethylenediamine tetraacetic acid (EDTA), fully maleated rosin,maleated tall-oil fatty acids, fumaric acid, glutaric acid, isophthalicacid, itaconic acid, maleated rosin oxidized with potassium peroxide toalcohol then carboxylic acid, maleic acid, malic acid, mesaconic acid,biphenol A or bisphenol F reacted via the KOLBE-Schmidt reaction withcarbon dioxide to introduce 3-4 carboxyl groups, oxalic acid, phthalicacid, sebacic acid, succinic acid, tartaric acid, terephthalic acid,tetrabromophthalic acid, tetrachlorophthalic acid, tetrahydrophthalicacid, trimellitic acid, trimesic acid, and the like, and anhydrides, andcombinations thereof.

Illustratively, a polymeric polycarboxylic acid may be an acid, forexample, polyacrylic acid, polymethacrylic acid, polymaleic acid, andlike polymeric polycarboxylic acids, copolymers thereof, anhydridesthereof, and mixtures thereof. Examples of commercially availablepolyacrylic acids include AQUASET-529 (Rohm & Haas, Philadelphia, PA,USA), CRITERION 2000 (Kemira, Helsinki, Finland, Europe), NF1 (H.B.Fuller, St. Paul, MN, USA), and SOKALAN (BASF, Ludwigshafen, Germany,Europe). With respect to SOKALAN, this is a water-soluble polyacryliccopolymer of acrylic acid and maleic acid, having a molecular weight ofapproximately 4000. AQUASET-529 is a composition containing polyacrylicacid cross-linked with glycerol, also containing sodium hypophosphite asa catalyst. CRITERION 2000 is an acidic solution of a partial salt ofpolyacrylic acid, having a molecular weight of approximately 2000. Withrespect to NF1, this is a copolymer containing carboxylic acidfunctionality and hydroxy functionality, as well as units with neitherfunctionality; NF1 also contains chain transfer agents, such as sodiumhypophosphite or organophosphate catalysts.

Further, compositions including polymeric polycarboxylic acids are alsocontemplated to be useful in preparing the binders described herein,such as those compositions described in U.S. Pat. Nos. 5,318,990,5,661,213, 6,136,916, and 6,331,350, the disclosures of which are herebyincorporated herein by reference. In particular, in U.S. Pat. Nos.5,318,990 and 6,331,350, an aqueous solution of a polymericpolycarboxylic acid, a polyol, and a catalyst is described. As describedin U.S. Pat. Nos. 5,318,990 and 6,331,350, the polymeric polycarboxylicacid comprises an organic polymer or oligomer containing more than onependant carboxy group. The polymeric polycarboxylic acid may be ahomopolymer or copolymer prepared from unsaturated carboxylic acidsincluding, but not necessarily limited to, acrylic acid, methacrylicacid, crotonic acid, isocrotonic acid, maleic acid, cinnamic acid,2-methylmaleic acid, itaconic acid, 2-methylitaconic acid,α,β-methyleneglutaric acid, and the like. Alternatively, the polymericpolycarboxylic acid may be prepared from unsaturated anhydridesincluding, but not necessarily limited to, maleic anhydride, itaconicanhydride, acrylic anhydride, methacrylic anhydride, and the like, aswell as mixtures thereof. Methods for polymerizing these acids andanhydrides are well-known in the chemical art. The polymericpolycarboxylic acid may additionally comprise a copolymer of one or moreof the aforementioned unsaturated carboxylic acids or anhydrides and oneor more vinyl compounds including, but not necessarily limited to,styrene, α-methylstyrene, acrylonitrile, methacrylonitrile, methylacrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, methylmethacrylate, n-butyl methacrylate, isobutyl methacrylate, glycidylmethacrylate, vinyl methyl ether, vinyl acetate, and the like. Methodsfor preparing these copolymers are well-known in the art. The polymericpolycarboxylic acids may comprise homopolymers and copolymers ofpolyacrylic acid. The molecular weight of the polymeric polycarboxylicacid, and in particular polyacrylic acid polymer, may be less than10000, less than 5000, or about 3000 or less. For example, the molecularweight may be 2000.

Preferred cross-linkers are selected from ammonium salts of inorganicacids, such as ammonium sulphate or ammonium phosphate, and ammoniumsalts of carboxylic acids. Further suitable cross-linkers are salt,ester and anhydride derivatives of carboxylic acids, preferablypolycarboxylic acids, more preferably monomeric polycarboxylic acids.

In a further aspect, the present invention relates to a compositematerial obtained by the method of the invention, the said compositematerial comprising a reduced furfural and/or hydroxymethylfurfuralcontent as compared with a composite material obtained from the same rawmaterial transformed under the same processing conditions but with noadded amine compound comprising at least one, preferably at least twoamine functions, wherein the amine functions are primary or secondaryamines.

The binder composition may be used in the manufacturing of compositeproducts, such as wood boards, for example wood particle boards, mediumdensity fibreboard (MDF), chip boards or orientated strand board (OSB),and plywood. The binder may be used to bond abrasive particles togetherand/or onto a backing sheet or to bond fibers, such as woven andnon-woven natural, synthetic, textile or mineral fibers, for instanceglass fibers or mineral wool fibers. Such bonded mineral fibers, forinstance mineral glass wool or stone wool fibers, may be used in themanufacturing of thermal and/or acoustic insulating materials.

A wood particle board is a composite material manufactured from woodparticles, for example wood chips, sawmill shavings and/or saw dust atvarying particle sizes held together by a binder and used especially forthe manufacture of furniture, such as cabinets, kitchens and bathroomfurniture. Generally, wood particle board (which is sometimes referredto as “chipboard”) is produced by mixing wood particles and a bindercomposition, e.g. a thermo-curable resin, subsequently forming theresulting mixture into a sheet or mat and compressing said sheet or matunder elevated temperatures.

Plywood is a composite sheet material manufactured from thin layers ofwood glued together by a binder, adjacent wood layers having their woodgrain rotated by approx. 90 degrees to one another.

When used as a binder in wood boards, such as plywood, particle boards,fiber boards, the solid content of the aqueous binder composition mayrange from 50 to 95 w %, preferably 50 to 90 w %, more preferably 55 to85 w % or even 60 to 80 w %, based upon the weight of the total aqueousbinder composition.

The binder may also be used to bond synthetic or natural fibers, forinstance mineral fibers, such as glass fibers, glass wool or stone wool.In view of the manufacture of a fiber mat, such as for insulatingproducts, for instance, an aqueous binder composition is applied ontothe fibers, e.g. by spraying, and the binder impregnated mineral fibersare deposited as a mat and subsequently subjected to heat for curing ofthe binder composition, hence forming an assembly of bonded fibers.

When used in the manufacture of a fiber based composite, the solidcontent of the invention aqueous binder composition may range from 5 to95 w %, advantageously from 8 to 90 w %, preferably from 10 to 85 w %,based on the weight of the total aqueous binder composition. Morespecifically, when used as a binder for mineral wool insulation, thesolid content of the aqueous binder composition may be in the range from5 to 25 w %, preferably from 8 to 20 w %, more preferably from 10 to 20w % or even 12 to 18 w %, based on the weight of the total aqueousbinder composition.

In the binder composition, the carbohydrate component is advantageouslypresent in an amount ranging from 30%, preferably from 40%, preferablyfrom 50%, more preferably from 60%, more preferably from 70%, even morepreferably from 80% by dry weight of the binder composition, to lessthan 97% more preferably less than 95% by dry weight of the bindercomposition.

The crosslinker may make up:

-   -   less than 50% or 40%, preferably less than 30%, more preferably        less than 25% by dry weight of the binder composition; and/or    -   at least 2.5%, preferably at least 5%, more preferably at least        10% by dry weight of the binder composition.

The binder composition may comprise at least 25%, and preferably atleast 40%, at least 50% or at least 60% by dry weight of: (a)carbohydrate component and crosslinker and/or (b) curable reactionproduct(s) of carbohydrate component and crosslinker.

The crosslinker and the carbohydrate component (or their reactionproduct(s)) may be Maillard reactants that react to form Maillardreaction products, notably melanoidins when cured. Curing of the bindercomposition may comprise or consist essentially of Maillard reaction(s).The cured binder is preferably a thermoset binder and is preferablysubstantially water insoluble.

The binder composition may further comprise one or more adjuvants, forexample waxes, dyes, release agents, formaldehyde scavengers,hydrophobizing agents and other adjuvants commonly used in bindercompositions. In certain applications, such as for example the bondingof mineral fibers, coupling agents, such as for example silicon-basedcoupling agents may advantageously be combined with the bindercomponents in the binder composition. Also, catalysts, such as mineralphosphorous-based salts and/or acids, such as phosphate or hypophosphitesalts, may be added into the binder composition as catalysts of theresin forming reaction.

Further advantages of the invention will become apparent from theExamples herein below.

FIG. 1 is a chart showing the variation of furfural content in a binderderived from a carbohydrate component comprising dextrose and xylose invarying amounts, cross-linked with ammonium sulphate, as well as theeffect of added hexamethylenediamine.

Example 1

Dextrose and varying amounts of xylose were dissolved in water toconstitute different carbohydrate components. These carbohydratecomponents were combined with ammonium sulphate cross-linker (AMS) toform aqueous binder compositions at a dry weight ratio ofcarbohydrate/AMS of 85/15 and at 37.5 wt. % solids. The same procedurewas repeated with binder compositions as above further comprising 2 and4 wt. % hexamethylene diamine. GFA glass filters were impregnated withthe relevant binders at a rate of 15% by weight cured solids, and curedduring 5 min at 180° C.

The furfural concentration of the cured binder was determined byleaching the impregnated filter into a small quantity of water at roomtemperature for 1 hour and analysing the leachate for furfural andhydroxyfurfural by HPLC (C18 column, acetonitrile/water mobile phase, UVdetector). The results were plotted in a chart as per FIG. 1 whichclearly shows that addition of small amounts of hexamethylene diaminesignificantly depresses furfural generation.

Example 2

The same experiment as above was repeated for the compositions shown inthe Tables below, in comparison with corresponding compositionscontaining no amine.

As can be understood, added urea, lysine and some further polyaminesefficiently reduce furfural concentration in the leachate.

TABLE 1 Furfural reduction in 85/15 glucose/ (NH₄)₂SO₄ bindercompositions % Reduction in % Reduction in Furfural + Furfural + Amine2% amine 4% amine HMDA  8% 95% Lupasol FG  9% 48% Urea 36% 47% TETA 16%46% Triethylenetetramine Lysine  7% 22% Luredur VM  0% 16% Ethylamine 0%  0% Jeffamine T-403  0%  0%

TABLE 2 Furfural reduction in 85/15 sugar/(NH₄)₂SO₄ binder compositions,wherein the sugar composition comprises 60% wt. glucose and 40% wt.xylose. % Reduction in % Reduction in Furfural + Furfural + Amine 2%amine 4% amine HMDA 27% 98% Lysine 16% 29% TETA 15% 26%Triethylenetetramine Lupasol FG  6% 23% Urea 12% 22% Jeffamine T-403  9%19% Ethylamine  2% 18% Luredur VM  0%  6%

In the Tables above,

HMDA stands for hexamethylenediamine

Lupasol FG (commercial name) is a polyethylenimine

Jeffamine T-403 (commercial name) is a polyetheramine

Luredur VM (commercial name) is a polyvinylamine

1. A method for the preparation of a composite product comprising fibersand/or particles and/or sheet material bonded with a carbohydrate-basedbinder comprising (i) providing a binder composition comprising acarbohydrate component and at least 10% by dry weight of the bindercomposition and less than 50% by dry weight of the binder composition ofa cross-linker and, optionally, a reaction product of the carbohydratecomponent and the cross-linker, wherein the carbohydrate component isderived from higher molecular weight carbohydrates wherein the level ofC5-sugars or five membered ring sugars varies from 10 to 70 wt. %, andwherein the cross-linker is selected from ammonium salts of inorganicacids, carboxylic acids, ammonium salts thereof, ester or anhydridederivatives thereof, and/or combinations thereof, (ii) adding to thebinder composition an additional amount of from 0.5 to 10 wt. % (basedon the total dry weight of the binder composition) of an amine compoundcomprising at least two amine functions, wherein the amine functions areprimary or secondary amines, and the amine compound is selected from (a)aliphatic monoamines, the aliphatic group being a straight or branchedsaturated or unsaturated alkyl or hetero-alkyl chain having 2 to 24C-atoms or cycloalkyl or cyclohetero-alkyl or an aromatic carbon ringstructure, each optionally substituted by hydroxy, carboxyl, halo,cyanate, sulfonyl or thiol, (b) compounds of general formula H₂N-Q-NH₂wherein Q is a straight or branched alkyl or heteroalkyl having 2 to 24C-atoms, cycloalkyl, or cylcoheteroalkyl, an aromatic carbon ringstructure, optionally substituted by hydroxy, carboxyl, halo, cyanate,sulfonyl and/or thiol, (c) whey or soy protein, optionally modified ordenatured, (d) poly(primary amines) having a molecular weight of 5000 orless and 10 wt. or more of primary amine groups based on the weight ofthe polyamine, (e) polyamino acids selected from lysine, ornithine,diaminobutyric acid and diaminopropionic acid, or (f) urea, (iii)applying the composition obtained under (ii) onto the fibers, particlesand/or sheet material, and (iv) subjecting the product obtained under(iii) to heat and optionally pressure to effect drying and/or curing. 2.The method according to claim 1, wherein the cross-linker is ammoniumsulphate or ammonium phosphate.
 3. The method according to claim 1,wherein the cross-linker is a carboxylic acid, ammonium salts thereof,or ester or anhydride derivatives thereof.
 4. The method according toclaim 1, wherein the carbohydrate is selected from monosaccharides,disaccharides, oligosaccharides and polysaccharides and/or combinationsthereof.
 5. The method according to claim 1, wherein the carbohydratecomponent is a polysaccharide selected from or derived from molasses,starch, starch hydrolysates, dextrines and derivatives thereof,cellulose hydrolysates, hemicellulose hydrolysates or mixtures thereof.6. The method according to claim 1, wherein the carbohydrate componentis present in an amount ranging from 30% by dry weight of the bindercomposition to less than 97% by dry weight of the binder composition.7.-11. (canceled)
 12. A method to reduce the level of furfural and/orhydroxymethylfurfural in a carbohydrate-based binder composition orbinder and/or escaping from carbohydrate-based binders in the course ofpreparation, cross-linking and/or curing thereof, comprising theaddition of an amine compound comprising at least two amine functions,wherein the amine functions are primary or secondary amines, to thebinder composition during binder preparation and prior to curing,wherein the amine compound is selected from (a) aliphatic monoamines,the aliphatic group being a straight or branched saturated orunsaturated alkyl or hetero-alkyl chain having 2 to 24 C-atoms orcycloalkyl or cyclohetero-alkyl or an aromatic carbon ring structure,each optionally substituted by hydroxy, carboxyl, halo, cyanate,sulfonyl or thiol, (b) compounds of general formula H₂N-Q-NH₂ wherein Qis a straight or branched alkyl or heteroalkyl having 2 to 24 C-atoms,cycloalkyl, or cylcoheteroalkyl, an aromatic carbon ring structure,optionally substituted by hydroxy, carboxyl, halo, cyanate, sulfonyland/or thiol, (c) whey or soy protein, optionally modified or denatured,(d) poly(primary amines) having a molecular weight of 5000 or less and10 wt. % or more of primary amine groups based on the weight of thepolyamine, (e) polyamino acids selected from lysine, ornithine,diaminobutyric acid and diaminopropionic acid, or (f) urea, wherein thecarbohydrate-based binder is obtained from a carbohydrate-based bindercomposition comprising a carbohydrate component and at least 10% by dryweight of the binder composition and less than 50% by dry weight of thebinder composition of a cross-linker and, optionally, a reaction productof the carbohydrate component and the cross-linker, wherein thecross-linker is selected from ammonium salts of inorganic acids,carboxylic acids, ammonium salts thereof, ester or anhydride derivativesthereof, and/or combinations thereof, wherein the carbohydrate componentis derived from carbohydrates wherein the level of C5-sugars or fivemembered ring sugars varies from 10 to 70 wt. %, and wherein the aminecompound is used in an amount of from 0.5 to 10 wt. % based on the totaldry weight of the binder composition.
 13. The method according to claim12, wherein the amine compound is a poly(primary amine) having amolecular weight of 5000 or less and 10 wt. % or more of primary aminegroups based on the weight of the polyamine, wherein the poly(primaryamine) is selected from polyetheramines, polyethyleneimines,polyethyleneimine-containing copolymers and block copolymers,polyvinylamines, and (co)polymers of aminoethyl methacrylate.
 14. Themethod according to claim 12, wherein the carbohydrate component ispresent in an amount ranging from 30% by dry weight of the bindercomposition to less than 97% by dry weight of the binder composition.15.-24. (canceled)
 25. The method according to claim 1, wherein theamine compound is a poly(primary amine) having a molecular weight of5000 or less and 10 wt. % or more of primary amine groups based on theweight of the polyamine, wherein the poly(primary amine) is selectedfrom polyetheramines, polyethyleneimines, polyethyleneimine-containingcopolymers and block copolymers, polyvinylamines, and (co)polymers ofaminoethyl methacrylate.